The present invention relates broadly to a sealing construction for providing a fluid seal intermediate a pair of opposed, mating parts or structures, and more particularly to a combination metal and elastomer gasket construction adapted to provide a fluid seal between such mating structures as aircraft wings and fuel access panels having faying surfaces which exhibit a simple or compound curvature.
Gaskets of the type herein involved are employed in a variety of sealing applications, such as in commercial, industrial, or military equipment, vehicles, or aircraft for compression between the opposing or faying surfaces of a pair of mating parts or structures to provide a fluid-tight interface sealing thereof. In basic construction, such gaskets are typically are formed of a relatively compressible, annular seal member having a central aperture configured for registration with the corresponding margins of the surfaces.
The seal member typically is supported by an annular metal or plastic retainer. In such an arrangement, the retainer is stamped or molded to conform to the surface geometry of the mating structures, with the seal member being molded-in-place in a groove formed into one or both sides of the retainer, or about the inner and/or outer periphery of the retainer to form an integral gasket structure. Representative retainer-supported gaskets are shown, for example, in U.S. Pat. Nos. 3,195,906; 3,215,442; 3,259,404; 3,578,346; 3,635,480; 3,720,420; 3,746,348; and 4,026,565, and are marketed commercially by the O-Seal Division of Parker-Hannifin Corporation, San Diego, Calif., under the tradename xe2x80x9cIntegral Seals.xe2x80x9d
In service, the gasket is clamped between the mating surfaces to effect the compression and deformation of the seal member and to develop a fluid-tight interface with each of those surfaces. Most often, the compressive force is provided using a circumferentially spaced-apart arrangement of bolts or other fastening members, each of which is received through an indexed pair of bores formed within the surfaces. Depending upon the geometry of the gasket, the fastening members also may be indexed through corresponding apertures formed within the seal or retainer member of the gasket.
Heretofore, the sealing of surfaces having a single degree of curvature or multiple, i.e., compound, degrees of curvature generally dictated that the retainer of the gasket be preformed into the desired shape prior to installation. However, and as is described in U.S. Pat. Nos. 4,254,960 and 4,321,225, the molding of seal elements onto a curved retainer requires special tooling. Alternatively, the gasket can be made flat and then pressed or otherwise bent into shape in a separate forming operation. With either of the present options, the cost associated with the manufacture of a curved gasket is increased over that of a comparable flat gasket.
Moreover, curved gaskets are often used to seal mirror-imaged parts, such as corresponding fuel access panels on the left and right sides of an aircraft. In service, however, the gaskets for the respective sides of the aircraft cannot be interchanged and therefore must be segregated to avoid xe2x80x9cpart confusion.xe2x80x9d
In view of the foregoing, it is apparent that improvements in the manufacture of metal and elastomer gaskets for curved surfaces would be well-received by industry. A preferred gasket construction would be economical to manufacture, but also would exhibit reliable sealing performance. Such a gasket additionally would be capable of providing fluid sealing with a minimum of compression set and resultant torque loss.
The present invention is directed to a gasket construction particularly adapted for providing a fluid-tight seal intermediate an opposing pair of curved interface surfaces such as may be found between an aircraft wing and a mating fuel access door. The gasket includes a generally planar retainer which extends within the plane thereof to a first dimension along at least one first radial axis, and to a second radial dimension along at least one second axis disposed generally normal to the first axis. The retainer further has an inner and an outer diametric extent which define an inner and outer perimeter of a closed geometric shape. At least one generally annular seal member formed of an elastomeric material is bonded or otherwise integrally attached to one or both of the inner or outer periphery of the retainer to be compressible intermediate a pair of interface surfaces for providing a fluid-tight seal therebetween.
In accordance with the precepts of the present invention, the retainer is stamped or otherwise formed of a thin, i.e., preferably about 25 mil or less, sheet of aluminum or other metal to be resiliently flexible in the first dimension along a first radius of curvature and in the second direction along a second radius of curvature. In this way, the gasket may be made to conform in an axially stressed state to simple or compound curved interface surfaces for the fluid-tight sealing thereof. However, in being resilient, the gasket is able to return to its generally planar normal state without appreciable permanent deformation or set.
Advantageously, the gasket of the invention therefore may be employed to provide a seal between, for example, a curved or compound curved aircraft wing and a mating fuel access door without the need and expense of having to pre-form the gasket into a curved shape. In this regard, the gasket also is particularly suited for use in field repairs or retrofit applications in eliminating the need to shape the gasket prior to installation. Moreover, in having a flat, normal orientation, a single gasket configuration may be interchangeably used for mirror-imaged parts without having to provide separate, side-specific configurations. Such capability provides additional cost savings and further eliminates the potential for xe2x80x9cpart confusion.xe2x80x9d
The present invention, accordingly, comprises the apparatus and method possessing the construction, combination of elements, and arrangement of parts and steps which are exemplified in the detailed disclosure to follow. Advantages of the present invention include a scaling gasket construction which exhibits reliable sealing properties and torque retention with a minimum of compression set. Additional advantages include a gasket construction which is economical to manufacture, and which may be used to seal simple or compound curved surfaces. These and other advantages will be readily apparent to those skilled in the art based upon the disclosure contained herein.